The present invention relates generally to electrical power generation systems, and more particularly a self-monitoring system and method for protecting an electrical power generator by identifying, preventing, and/or correcting system faults that occur.
Electrical generators are used in a wide variety of dedicated electrical system applications and locations that require power independent of a standard electrical grid. Commonly, electrical generators are the primary, if not only, source of electrical power on a vehicle or ship, or in a remote location such as on an oil platform, in a small town, on an island or along a pipeline. Electrical generators are also commonly used as a backup power source in locations operating primarily off the standard electrical grid.
Because of this primary role served by electrical generators, it is often desired to keep the generator fully functioning, or at least partially functioning, in all circumstances. Maintaining the generator at full capacity is complicated by the fact that the conventional generator is a slave to its loads, the maximum sum of which may greatly exceed a rated capacity of the generator. The generator itself cannot directly control its outputted power; it can only control its own output voltage. Rather, it is the generator's loads that control the draw of power from the generator.
To avoid operational conditions that may harm the generator, conventional generator protection strategies dictate that the generator simply be shut off upon the detection of any abnormalities. While effective in protecting the generator, this solution is far from ideal as the generator is often the only energy source for the loads and it can take some time to restart the generator.
In detecting and identifying abnormalities that will trigger a hard shut down of the generator, conventional protection strategies monitor temperature, output voltage, output current, and/or output power of the generator for values in excess of some predetermined threshold. Such detection strategies are generally designed to maintain the generator operations well within some predetermined margins, that is, to keep the generator far away from any operating conditions where it might become unstable, or where an overtemperature or overcurrent might be experienced. These strategies, however, have the unwelcome effect of significantly limiting the effective power capacity of the generator.
Generators typically have a rated continuous capacity that is determined as the maximum quantity of power the generator can produce for an indefinite amount of time without risking damage to the generator. Generators also have a rated surge capacity determined as a value the generator can sustain for a limited time, such as when the generator experiences a surge in power demands due to the transitioning of the generator's loads between on and off states. These rated continuous and surge capacities are typically very conservative estimates of what the generator can actually handle. By conservatively maintaining the generator within these artificial boundaries, conventional protection strategies are unnecessarily sacrificing a significant capacity of the generator.
Thus, a need exists for protection strategies that protect the generator and its loads, while avoiding unnecessary generator shut downs and undue constraints on the generator's capacity.